Method of making sealing strip



July 15, 1969 R. H. COLLINS 3,

METHOD OF MAKING SEALING STRIP Filed Nov. 8, 1965 INVENTOR. Fit/$411 /7.' 60/7/21;

United States Patent "cc US. Cl. 29-527.1 1 Claim ABSTRACT OF THE DISCLOSURE This disclosure relates to an improved method for forming a carrier for sealing strip by transversely slitting the carrier, stretching the carrier to produce slots therein and encasing said carrier in a layer of resilient sealing material.

This invention relates generally to a method of forming sealing or trim strips and more particularly to an improved carrier for trim and sealing strips and to a method for forming such a carrier.

Trim or sealing strips used in motor vehicles generally are of channel shape so as to be capable of gripping a complementary flange on the vehicle. Such trim and sealing strips must be sufficiently flexible to permit the strip to be deformed so that it can follow the contour of, for example, doors of the vehicle, yet be sufliciently rigid so that the strip will retain itself upon the complementary flange without additional fastening means.

It has been common practice in the art to provide such trim or sealing strips with a perforated metallic core or carrier around which a resilient trim or sealing material is formed. The metallic core or carrier gives the required gripping ability to the trim or sealing strip while the perforations thereof permit it to be somewhat flexible. However, the material removed from the carrier to form the perforations constitute waste which increases the manufacturing cost.

In accordance with the instant invention, a core or carrier for trim and sealing strip embodying this invention comprises a longitudinally extending central web portion having laterally extending integrally connected tab portions. The tab portions are folded relative to the web portion to define a channel or U-shaped cross section. The tabs are spaced from each other to impart flexibility to the trim strip, being interconnected only through the web. A resilient trim or sealing material encases the web and tab portions of the carrier and fills the spaces between the tabs.

The problem of waste material is solved, in accordance with another feature of the instant invention, by forming the carrier by laterally slitting an elongated strip of relatively thin steel inwardly from opposite edges thereof at longitudinally spaced positions to define the tabs leaving a thin connecting web running the length of the carrier centrally thereof. Tension is then applied to the slit core or carrier in the longitudinal direction to permanently deform and elongate the web to and thereby longitudinally separate the outer extremities of the tabs. The elongated carrier is then encased with resilient trim or sealing material with the sealing material encompassing the web and tabs and filling the gaps between the tabs.

Accordingly, one object of this invention, therefore, is a method of forming an improved core or carrier for trim and sealing strip that eliminates waste material, is easy to manufacture, and retains a desired balance between flexibility and holding power.

Other objects and advantages of the invention will be apparent when considered in conjunction with the appended claims, detailed description and drawings, wherein:

3,455,018 Patented July 15, 1969 FIGURES 1 through 4 illustrate the steps of forming a trim or sealing strip emboying this invention, FIGURE 11 illustrating the core or carrier member after it has been sit;

FIGURE 2 illustrates the slit core or carrier member after it has been expanded;

FIGURE 3 illustrates the coating of the core or carrier member encased within a resilient material; and

FIGURE 4 illustrates the shape of the completed trim or sealing strip.

Referring now in detail to the drawings and in particular to FIGURE 4, a segment of the completed trim or sealing strip embodying this invention is indicated generally by the reference numeral 11. The trim or sealing strip 11 is comprised of a core member 12 that is encased within a resilient sealing material 13.

The core member 12 is formed from sheet metal or some other similar material that has the desired degree of resilience to permit bending of the sealing strip 11 to conform to the shape of the member to be trimmed or sealed. The core member 12 is generally of a channel or horseshoe shape and is comprised of a longitudinally extending web portion 14 that runs the length of the core member 12 and from which integrally connected tabs 15 extend. The tabs extend downwardly and outwardly from the web 14 to provide the channel shape and gaps 16 are formed between each of the tabs 15 so that the tabs are connected to each other only through the web 14.

The trim or sealing material 13, which may be of any known type, for example, vinyl, encircles and encompasses the web 14 and tabs 15 of the core member 12 and completely fills the gap 16 between the tabs 15. A pair of resilient gripping flanges 17 and '18 are formed integrally with the trim or sealing material 13 adjacent the lower ends of the tabs 15 and extend upwardly and inwardly into the channel defined by the tabs 15. The gripping flanges 17 and 18 are adapted to grippingly engage a pinch weld flange of a motor vehicle body or other similar structure to retain the sealing strip 11 with respect to the vehicle flange.

Referring now to the method in which the sealing strip 11 is made, the elongated core member 12 is made from a flat strip and is formed with a plurality of longitudinally spaced slits 21 that extend from opposite edges of the core member toward their center (FIG. 1). The slits 21 at each side of the core member 12. are longitudinally aligned but do not intersect and thus leave the web 14 therebetween.

After the slits 21 are formed, the core member 12 is expanded by exerting a tensile force thereon (FIG. 2). The expansion of the core member 12 causes the gaps 16 to be formed between the tabs 15 through a permanent deformation of the web portion 14 that reduces its thickness. This deformation weakens the web 14 particularly in the area adjacent the gaps 16. If desired, the web may be notched or otherwise scored to promote its fracturing upon bending of the completed sealing strip 11.

The expanded web 12 is then encased with the sealing material 13, as by an extrusion process. Simultaneous with the encasement of the core 12 within the sealing material 13, the gripping flanges 17 and 18 are formed (FIG. 3). The flanges 17 and 18 are formed on the same side of the core member 12 adjacent the outer terminus of the tabs 15 at the respective sides.

The core 12 and encasing resilient sealing material 13 are then deformed into a channel shape (FIG. 4) by any suitable forming action, for example, rolling. During this forming operation, the core member 12 is permanently deformed and thus the sealing strip 11 retains this shape. The gripping flanges 17 and 18 are brought in abutting relationship during the forming operation so that they will be in a position to grip a pinch weld flange therebetween.

The sealing strip 11 may be twisted about its longitudinal axis or may be otherwise-deformedto conform to the shape of the vehicle flange that is being trimmed. The web 14, which has been weakened as a result of the expanding step, may fracture during this bending operation. Such fracturing of the web is not detrimental to the operation of the sealing strip 11 since the web 14 does not perform any function once it is encased within the sealing material 13. The tabs 15 serve to add sutficient rigidity to the sealing strip 11 to retain it upon the vehicle flange. The fracture of the web 14 can be promoted through scoring or other weakening of it, as has been previously noted, if desired.

It is to be understood that the specific construction of the sealing strip herein disclosed and described is presented for the purpose of explanation and illustration and is not intended to indicate limits of the invention, the scope of which is defined by the following claim.

What is claimed is:

1. The method of forming a sealing strip comprising the steps of:

slitting an elongated core member at a plurality of longitudinally spaced positions from opposite edges to form a centrally located relatively thin connecting web running the length of the core member and from which tabs extend, the tabs being connected to each other only by the web,

"expanding the core member in a longitudinal direction by exerting a tensile force on the web portion thereof to permanently deform and weaken the web and separate the tabs with gaps therebetween, and

encasing the core member with a layer of resilient sealing material with the sealing material encompassing the web and tabs and filling the gaps between the tabs.

References Cited UNITED STATES PATENTS 2,954,3l0 9/1960 Truesdell et al. 52-716 X 3,167,856 2/1965 Zoller 29413 3,222,769 12/1965 Le Plae 29527 X 3,310,928 3/1967 Weimar 52-716 CHARLIE T. MOON, Primary Examiner US. Cl. X.R. 

